CN103050133B - Glass base plate for magnetic recording carrier and employ the magnetic recording media of this glass base plate for magnetic recording carrier - Google Patents
Glass base plate for magnetic recording carrier and employ the magnetic recording media of this glass base plate for magnetic recording carrier Download PDFInfo
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- CN103050133B CN103050133B CN201210385806.8A CN201210385806A CN103050133B CN 103050133 B CN103050133 B CN 103050133B CN 201210385806 A CN201210385806 A CN 201210385806A CN 103050133 B CN103050133 B CN 103050133B
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Abstract
It is an object of the invention to provide a kind of glass base plate for magnetic recording carrier and employ the magnetic recording media of this glass base plate for magnetic recording carrier, wherein, when cancellate each evaluation region of the set overall of at least one principal plane (record regenerating face) of glass base plate for magnetic recording carrier determines surface roughness Ra, its maximum is in the range of regulation.A kind of glass base plate for magnetic recording carrier is provided and employs the magnetic recording media of this glass base plate for magnetic recording carrier, this glass base plate for magnetic recording carrier has a pair principal plane, it is characterized in that, on at least one principal plane, the maximum of the surface roughness Ra that the cancellate each evaluation region set on whole of principal plane is measured to is as less than 1.7 times of meansigma methods of described surface roughness Ra.
Description
Technical field
The present invention relates to glass base plate for magnetic recording carrier and employ the magnetic recording of this glass base plate for magnetic recording carrier
Medium.
Background technology
As at middle magnetic recording media substrates used such as magnetic disc recording devices, in the past, employ aluminium alloy base plate.So
And, in recent years, along with the requirement of high density recording, harder and flatness, flatness are excellent compared with aluminium alloy base plate
Glass substrate becomes main flow.
Further, along with the high record density of disk (hereinafter also referred to as magnetic recording media) in recent years, on disk
Record of magnetic signal imperceptibly, is accompanied by this, and signal is faint.Reading and record for this faint signal, it is desirable to as far as possible
Shorten the distance of disk and magnetic head.
In order to reduce the floatation volume of distance between disk rotate at high speed and magnetic head, i.e. magnetic head, need to make disk
The substrate i.e. surface of glass base plate for magnetic recording carrier is the most homogeneous surface, to avoid disk to come in contact with magnetic head.
In order to reduce the distance between magnetic head and disk, and the surface characteristic for glass base plate for magnetic recording carrier is carried out
Various discussion.The shape such as having recorded the defect being present in glass substrate for disc in patent documentation 1 impacts, and
The situation below value making surface roughness Ra be regulation.
[citation]
[patent documentation]
[patent documentation 1] International Publication the 2010/001843rd
But, in patent documentation 1, by atomic force microscope only for glass base plate for magnetic recording carrier
The regional evaluation of a limited part in record regenerating region surface roughness Ra, most in record regenerating region
, on record regenerating region, therefore there is the region that the value of surface roughness Ra increases, have in region undetermined surface roughness Ra
Time can become problem.Such as, there is the floatation volume being difficult to reduce magnetic head and the instability of the distance between disk and magnetic head and produce
The problem of magnetic noise etc..
It addition, when manufacturing magnetic recording media, the surface filming at glass base plate for magnetic recording carrier goes out magnetosphere, but
The principal plane of glass base plate for magnetic recording carrier exists the high region of the value of surface roughness Ra, and (surface roughness Ra is inhomogenous
Region) time, the size of the magnetospheric crystal grain of film forming produces inhomogeneity sometimes.Have inhomogenous magnetosphere (crystal grain
The inhomogenous magnetosphere of size) magnetic recording media may produce magnetic noise on the inhomogenous region of size of crystal grain and increase
Add, the problem of degradation under the precise decreasing of the read-write to magnetic recording media based on magnetic head, packing density.
Summary of the invention
The problem that the present invention has in view of above-mentioned prior art, its object is to provide a kind of at magnetic recording media glass
On whole of at least one principal plane (record regenerating region) of substrate, surface roughness Ra is made to be in the range of regulation
Glass base plate for magnetic recording carrier.
In order to solve above-mentioned problem, the present invention provides a kind of glass base plate for magnetic recording carrier, has a pair principal plane, its
Being characterised by, at least one principal plane, the cancellate each evaluation region set on whole of principal plane is measured to
Less than 1.7 times of the meansigma methods that maximum is described surface roughness Ra of surface roughness Ra.
[invention effect]
The glass base plate for magnetic recording carrier (following, to be the most only recited as " glass substrate ") of the present invention, at glass base
Cancellate each evaluation region of whole setting of at least one principal plane of plate determines surface roughness (arithmetic average
Roughness) Ra time, its maximum and meansigma methods are in the relation of regulation.
Therefore, on whole of at least one principal plane of glass substrate, surface roughness Ra is in the scope of regulation
In, there is no the region that surface roughness Ra local is high, thus become whole homogeneous and smooth glass substrate of principal plane.
Glass base plate for magnetic recording carrier according to the present invention, using the teaching of the invention it is possible to provide a kind of formation magnetic on the surface of glass substrate
Property layer time suppression crystal grain coarsening, and the magnetic recording media that the magnetospheric surface with the size uniformity of crystal grain is smooth.
Thereby, it is possible to the generation of the magnetic noise of suppression magnetic recording media, make the distance ratio between magnetic recording media and magnetic head
Reduced in the past, made the stable distance between magnetic recording media and magnetic head, it is possible to make the read-write precision of the record of magnetic recording media
Raise than ever with packing density.
Accompanying drawing explanation
Fig. 1 is glass base plate for magnetic recording carrier and the explanatory diagram of evaluation region thereof of first embodiment of the present invention.
Detailed description of the invention
Hereinafter, referring to the drawings, the mode for implementing the present invention is described, but the invention is not limited in following embodiment party
Formula, can apply various deformation and displacement to embodiment disclosed below without departing from the scope of the present invention.
[the first embodiment]
In the present embodiment, the glass base plate for magnetic recording carrier for the present invention illustrates.
The glass base plate for magnetic recording carrier of the present invention is characterised by, at least the one of glass base plate for magnetic recording carrier
On individual principal plane, the surface roughness Ra that is measured to of cancellate each evaluation region set on whole of principal plane is
Big value is less than 1.7 times of the meansigma methods of surface roughness Ra.
About concrete evaluation methodology, Fig. 1 is used to illustrate.
As shown in Fig. 1 (A), glass base plate for magnetic recording carrier presents and has round-meshed disc-shape at central part.And
And, in the present invention, at least one principal plane of this glass substrate, i.e. as magnetic recording media time record regenerating region whole
In cancellate each evaluation region set on individual face, measure surface roughness Ra.As shown in Fig. 1 (A) and (B), by inciting somebody to action
Principal plane Ground Split very close to each other is that some forms evaluation region.Preferably evaluation region is formed as same shape.
For the assay method of surface roughness (arithmetic average roughness) Ra, and it is not particularly limited, as long as can measure
The surface roughness of cancellate each evaluation region it is set as in whole face.For example, it is possible to interfered micro-by sweep type
Mirrors etc. measure.
It is set as the shape of cancellate evaluation region, size and is not particularly limited, such as, as the shape of evaluation region
Shape, can list the shape of the grid such as square lattice, triangular lattice, hexagonal lattice, diamond check, rectangular grid, parallel body grid
Shape.
As the size of 1 evaluation region, such as at evaluation region when being shaped as square lattice, can be by the length on 1 limit
Degree is set in the range of 5 μm ~ 50 μm, for example, it can be set to be that 50 μm are square, 40 μm are square, 30 μm are square, 20 μm are square
Desired size.
It addition, in the case of being shaped as beyond square lattice of evaluation region, the size as standard can be set,
That is, so that the area of evaluation region becomes areal extent (such as, 25 μm identical with the situation of described square lattice2~2500μ
m2) mode set this size.It should be noted that below, for the size of evaluation region, describe with the 1 of square lattice
The situation of a length of benchmark on limit, but be not defined to square lattice, beyond square lattice in the case of represent as mark
Accurate size (area).
Additionally, be set as that the shape of cancellate evaluation region, size, can different (examples on whole of principal plane
As, the whole face of principal plane is divided into the region of regulation, sets the shape of evaluation region, size etc. at regional), preferably
Identical.
The most preferably each region in the size identical with magnetic head or smaller size is evaluated, therefore conduct
The size of evaluation region, preferably following is evaluated so that 50 μm are square, below more preferably 30 μm are square.
But, when evaluation region undersized, the number of evaluation region increases, and therefore data volume increases and it processes
Become difficulty, more than the most preferably 5 μm are square, more than more preferably 10 μm are square.
Here, evaluation region is illustrated.Fig. 1 (A), (B) schematically show each evaluation region.Need explanation
It is figure to illustrate line, but this is the line for evaluation region is described, rules the most on the glass substrate.Here, make
With the example of square lattice, evaluation region is described.
A part of Fig. 1 (A) is amplified by Fig. 1 (B) in order to evaluation region is described.Square lattice shown in Fig. 1 (B) is (just
Square) each piece (the such as part shown in (a) ~ (d)) represent evaluation region, such as the length A ~ F on 1 limit is all set as 30 μ
m。
Further, in the glass base plate for magnetic recording carrier of the present invention, by according to each evaluation overall for a principal plane
The result of the surface roughness of area test and the meansigma methods of surface roughness Ra that calculates is set to Raave.Additionally, surface is thick
The table of the evaluation region that the value of the surface roughness in the evaluation region that the maximum of rugosity Ra, the most described principal plane are overall is the highest
Surface roughness Ra is set to RamaxTime, meet Ramax≤1.7·RaaveRelation, i.e. the maximum of surface roughness Ra is surface
Less than 1.7 times of the meansigma methods of roughness Ra.
Here, about Raave、RamaxRelation, more preferably Ramax≤1.4·Raave, particularly preferably Ramax≤
1.3·Raave。
This is because along with the maximum of surface roughness Ra and the ratio of meansigma methods are close to 1.0, whole of principal plane
On, the variation of surface roughness Ra reduces, and represents smoother (that is, the Ra of principal plane of glass substratemax≥1.0·Raave).
It should be noted that there is two sides up and down at glass base plate for magnetic recording carrier in principal plane, but conduct the most sometimes
Become during disk record regenerating region for either one, the most only either one meets above-mentioned important document.When as disk, on
In the case of lower two sides all becomes record regenerating region, preferably upper and lower surface is according to respective mensuration, the rough surface that calculates
Meansigma methods and the maximum of degree Ra are satisfied by above-mentioned important document.This is for meansigma methods described later, standard deviation too.
Additionally, be set in the cancellate each evaluation region on whole of described principal plane the rough surface measured
The standard deviation of degree Ra is preferably below 0.012nm, more preferably below 0.010nm, particularly preferably below 0.008nm.
This is because, by reducing standard deviation, about whole of the principal plane of glass substrate, refer to surface roughness
The variation of Ra is little, represents that the principal plane of glass substrate is smoother.
So, whole of principal plane smooths and does not exist the region of the highest surface roughness Ra in local, is therefore being formed
Magnetosphere and during as magnetic recording media, the coarsening of suppression crystal grain local, the size uniformity of crystal grain such that it is able to obtain surface
Smooth magnetic film.
Therefore, it is possible to the distance shortened between disk (magnetic recording media) and magnetic head.And, between disk and magnetic head away from
From stable, therefore, it is possible to the generation of suppression magnetic noise, it is possible to make the read-write precision of record, packing density improve than ever.Additionally,
The magnetospheric magnetic recording media little and homogeneous by having the size of crystal grain, it is possible to reduce bit size such that it is able to real
The raising of the area recording density of existing magnetic recording media.
It addition, be set in the cancellate each evaluation region on whole of described principal plane the rough surface measured
The meansigma methods of degree Ra is preferably below 0.08nm, more preferably below 0.07nm.
This is because, by reducing the meansigma methods of surface roughness Ra, represent that the principal plane entirety of glass substrate is smoother.
If the principal plane entirety of glass substrate smooths, then, when forming magnetosphere, the coarsening of crystal grain can be suppressed, it is possible to make
The size of crystal grain reduces and homogeneous such that it is able to obtain uniform surface and smooth magnetic film.
Reduced and homogeneous and bit size can be reduced by the size making crystal grain such that it is able to realize magnetic recording media
The raising of area recording density.And, it is possible to reduce the distance between disk and magnetic head, and can reduce between disk and magnetic head
The variation of distance, it is possible to the generation of suppression magnetic noise, the most more improve the read-write precision of record, packing density.
Here, the manufacture method of the glass base plate for magnetic recording carrier of the present invention is illustrated.
Glass base plate for magnetic recording carrier can be by including the manufacture method manufacture of following operation 1 ~ 4.
(operation 1), by glass original substrate, is processed into after central part has the glass substrate of round-meshed disc-shape, right
Inner circumferential end face and peripheral end face carry out the shape of chamfer machining and give operation.
The end surface grinding operation that the end face (inner circumferential end face and peripheral end face) of glass substrate is ground by (operation 2).
The principal plane grinding step that the principal plane of described glass substrate is ground by (operation 3).
(operation 4) carries out precision cleaning the matting being dried to described glass substrate.
Then, the manufacture method comprising above-mentioned each operation is utilized and the glass base plate for magnetic recording carrier that obtains also is carried out
Form the operation of the thin film such as magnetosphere on it, it is possible to as magnetic recording media.
Here, the shape imparting operation of (operation 1) will be by float glass process, fusion method, punching formation, glass tube down-drawing or traction again
Method and the glass original substrate that shapes is processed into the glass substrate having round-meshed disc-shape at central part.It should be noted that
The glass original substrate used both can be amorphous glass, it is also possible to be sintered glass ceramics, it is also possible to be the table at glass substrate
Layer has the strengthening glass of compressive stress layers (strengthening layer).
Then, in the end surface grinding operation of (operation 2), end face (side surface part and chamfered section) to glass substrate carries out end face
Grind.
About the principal plane grinding step of (operation 3), use double-side polishing apparatus, supply to the principal plane of glass substrate
Principal plane up and down to lapping liquid simultaneous grinding glass substrate on one side.The grinding of the glass substrate of the present invention both can only implement 1
Secondary grinding, it is also possible to implement 1 time to grind and grind for 2 times, it is also possible to implement 3 times after 2 times are ground and grind.
Further, the grinding pad used in grinding step is preferably used and advances with pure water and carried out more than 10 minutes clear
The grinding pad washed.This is to suppress the coagulation of abrasive particle contained in lapping liquid.
It should be noted that as the grinding used when grinding (smooth grinding) finally implemented of principal plane grinding step
Liquid, be preferably used containing the cabosil that primary particle footpath is more than 5nm as abrasive particle, pH be the lapping liquid of more than 3.
This is because, the primary particle footpath of the cabosil contained in lapping liquid is easy coagulation time less than 5nm, can produce
The problems such as life cannot stably be ground, the surface roughness Ra increase of first type surface.
1 particle footpath of cabosil is preferably more than 5nm, more preferably more than 8nm, particularly preferably 10nm with
On.And, 1 particle footpath of cabosil is preferably below 30nm, more preferably below 28nm, particularly preferably 18nm with
Under.
It addition, when the pH of lapping liquid is less than 3, the surface of the principal plane of the glass substrate ground due to the impact of acid is thick
The value of rugosity Ra likely raises.Therefore, the pH of lapping liquid is preferably more than 3, more preferably more than 3.5, particularly preferably 4 with
On.
Before the principal plane grinding step of above-mentioned (operation 3), it is also possible to implement polishing (the lapping) (example of principal plane
As, free abrasive polishing, bonded-abrasive polishing etc.).And, the cleaning (operation of glass substrate can also be implemented at each inter process
Between clean), the etching (inter process etching) of glass baseplate surface.It should be noted that the polishing of principal plane refers to the master of broad sense
The grinding of plane.
Additionally, when glass base plate for magnetic recording carrier requires high mechanical strength, form pressure on the top layer of glass substrate
The strengthening operation (such as, chemical enhanced operation) of stress under compression layer (strengthening layer) can also before grinding step or after grinding step,
Or implement between grinding step.
[the second embodiment]
In the present embodiment, illustrate to employ the glass base plate for magnetic recording carrier that illustrates in the first embodiment
Magnetic recording media (disk).
As long as the magnetic recording media of the present invention employs the magnetic recording media glass base illustrated in the first embodiment
Plate, its structure is not defined, and include, for example out and possesses magnetosphere, protection on glass base plate for magnetic recording carrier surface
Layer, the structure of lubricating layer.
Magnetic recording media has horizontal return to zero, perpendicular magnetic recording, but at this with perpendicular magnetic recording is
Example, the manufacture method that following description is concrete.
Magnetic recording media at least possesses magnetosphere, protective layer, lubricating layer on its surface.Further, at perpendicular magnetic recording
In the case of, it is commonly configured with playing the soft magnetism that the soft magnetic material of the effect making the recording magnetic field circulation from magnetic head is constituted
Basal layer.Therefore, it is sequentially laminated with such as soft magnetic substrate coat, nonmagnetic intermediate layer from the principal plane of glass substrate, vertically remembers
Employ magnetosphere, protective layer, lubricating film.
Hereinafter, each layer is illustrated.
As soft magnetic substrate coat, it is possible to use such as CoNiFe, FeCoB, CoCuFe, NiFe, FeAlSi, FeTaN,
FeN, FeTaC, CoFeB, CoZrN etc..
Further, nonmagnetic intermediate layer is made up of Ru, Ru alloy etc..This nonmagnetic intermediate layer has for making perpendicular recording use
The easy function of magnetospheric epitaxial growth and the magnetic exchange between soft magnetic substrate coat with record magnetosphere is combined cut-out
Function.
Perpendicular recording magnetosphere be magnetize easy axle towards the magnetic film of the vertical direction vertical with real estate, at least wrap
Include Co, Pt.Further, in order to reduce the intergranular exchange of the reason of the intrinsic medium noise becoming high, and the most well every
From micropartical structure (grain structure).Specifically, use with the addition of oxide (SiO to CoPt system alloy etc.2、SiO、
Cr2O3、CoO、Ta2O3、TiO2Deng), the structure of Cr, B, Cu, Ta, Zr etc..
The soft magnetic substrate coat of explanation so far, nonmagnetic intermediate layer, perpendicular recording magnetosphere can be by online
Sputtering method, DC magnetron sputtering system etc. manufacture continuously.
It follows that protective layer prevents the magnetospheric corrosion of perpendicular recording, even and if in order to contact with medium at magnetic head
In the case of also can prevent the damage of dielectric surface from arranging, and be arranged on perpendicular recording magnetosphere.As protective layer, permissible
Use comprises C, ZrO2、SiO2Deng material.
As its forming method, such as, can use online sputtering method, CVD, spin-coating method etc..
It is formed with lubricating layer, to reduce the friction of magnetic head and record medium (disk) on the surface of protective layer.Lubricating layer can
To use such as PFPE, fluorinated alohol, fluorinated carboxylic etc..For lubricating layer, can be formed by infusion process, spurt method etc..
The magnetic recording media using the glass base plate for magnetic recording carrier of the present invention to make by order described above
In (disk), owing to the surface roughness Ra of the principal plane entirety of glass substrate is in the scope of regulation, therefore in film forming magnetic
The coarsening of crystal grain can be suppressed such that it is able to the size making crystal grain is little and homogeneous during layer.Thereby, it is possible to reduction magnetic recording media
Bit size, it is possible to increase the area recording density of magnetic recording media.Be additionally, since can make magnetic recording media and magnetic head it
Between distance reduce than ever, it is possible to reduce the variation of distance between magnetic recording media and magnetic head, therefore, it is possible to suppression magnetic is made an uproar
The generation of sound, compared with the past can improve the read-write precision of record, packing density.
[embodiment]
Hereinafter, enumerate specific embodiment and illustrate, but the present invention is not defined to these embodiments.
First, the evaluation methodology of glass base plate for magnetic recording carrier in below example, comparative example is described and at glass
On glass substrate surface, film forming goes out the evaluation methodology of the magnetic recording media of the thin film such as magnetosphere.
(1) surface roughness (arithmetic average roughness) Ra
Surface roughness Ra uses sweep type interference microscope (Zygo company system, ZeMapper) to be determined.Surface
The mensuration region of roughness Ra is the scope in whole of the record regenerating region including glass base plate for magnetic recording carrier.
In the present embodiment, whole of a principal plane of glass base plate for magnetic recording carrier sets 1 limit as 30 μ
The evaluation region of the square lattice shape of m, for each evaluation region, has obtained surface roughness Ra.
(2) test is proved
Prove the defect (signal quality) of the magnetosphere etc. of test evaluation magnetic recording media.Prove that test magnetic head uses
It is arranged at the measuring head of head slide piece, makes the magnetic head of disk set and the relation reappearing of disk, for each magnetic track each of dish
Individual carry out write signal write, regenerate, eliminate, regeneration etc. and evaluated.In the present embodiment, have rated EP
(Extra Pulse: extra pulse) mistake.
EP mistake refers to there is scar, foreign body, the roughness inhomogenous district of size bad, crystal grain on magnetic recording media
During territory, generation is from the regenerated signal of the bigger disengaging of amplitude of the regenerated signal of measuring head.EP mistake can not carry out the suitable of disk
Signal processing.
In the present embodiment, have rated 1000 magnetic recording medias, and the ratio of the magnetic recording media of EP mistake will be there occurs
Rate is set to EP incidence rate.
In following example 1 ~ example 10, illustrate glass base plate for magnetic recording carrier and on glass base plate for magnetic recording carrier shape
Become magnetosphere etc. and as the example of magnetic recording media.Here, example 1 ~ 7 is the embodiment of the regulation meeting the present invention, example 8 ~ 10
It it is comparative example.
The glass base plate for magnetic recording carrier of the example 1 ~ example 10 of following description is made by following order.
In order to obtain external diameter 65mm, internal diameter 20mm, the glass base plate for magnetic recording carrier of thickness of slab 0.635mm, will be by floating
Method shape with SiO2Glass substrate for main constituent is processed at the central part round-meshed disc-shape glass substrate of tool.
In order to obtain chamfering width 0.15mm, the glass base plate for magnetic recording carrier of chamfer angle 45 ° and to this disc
The inner circumferential end face of shape glass substrate and peripheral end face have carried out chamfer machining (inner circumferential chamfering process, periphery chamfering process).
After chamfer machining, use alumina abrasive grain principal plane upper and lower to glass substrate to carry out polishing processing, abrasive particle is cleaned
Remove.
Then, abrasive brush and the outer circumferential side to glass base plate for magnetic recording carrier of the lapping liquid containing cerium oxide abrasive particle are used
Face and periphery chamfered section are ground, and are removed by the affected layer (scar etc.) of circumferential lateral surface and periphery chamfered section, will outward
All end surface grindings are processed into minute surface (peripheral end face grinding step).
After the end surface grinding of periphery, use abrasive brush and the lapping liquid containing cerium oxide abrasive particle to magnetic recording media glass
The inner circumferential side face of substrate and inner circumferential chamfered section are ground, by the affected layer (wound of inner circumferential side face and inner circumferential chamfered section
Trace etc.) remove, inner circumferential end surface grinding is processed into minute surface (inner circumferential end surface grinding operation).After having carried out inner circumferential end surface grinding
Glass substrate, by abrasive particle clean remove.
After the end face of glass substrate has been carried out processing, use the fixed tablet instrument containing diamond abrasive particle and grinding
Liquid, principal plane upper and lower to glass substrate carries out polishing processing, cleans.
Then, as grinding apparatus, the grinding pad of hard polyaminoester and the lapping liquid containing cerium oxide abrasive particle is used (to put down
All particle diameters, hreinafter referred to as mean diameter, the lapping liquid constituent of the cerium oxide containing about 1.3 μm), double by 22B type
Face lapping device (SpeedFam company system, ProductName: DSM22B-6PV-4MH) becomes 20 μm at upper and lower principal plane with amount of grinding
Mode glass substrate is carried out 1 time grind, by cerium oxide clean remove.It should be noted that 216 glass of 1 batch of simultaneous grinding
Glass substrate.
Glass substrate after grinding for 1 time uses the grinding pad of flexibel polyurethane and containing mean diameter than above-mentioned oxidation
The lapping liquid (the lapping liquid constituent of the cerium oxide containing mean diameter about 0.5 μm) of the cerium oxide abrasive particle that cerium abrasive particle is little is as grinding
Mill apparatus, carries out 2 times by the way of 22B type double-side polishing apparatus becomes 5 μm with amount of grinding and grinds, by oxygen upper and lower principal plane
Change cerium and clean removing.
Glass substrate after grinding for 2 times carries out 3 times and grinds (smooth grinding).As the grinding apparatus of 3 grindings, use
Flexibel polyurethane grinding pad and the lapping liquid containing cabosil, carried out upper and lower principal plane by double-side polishing apparatus
Attrition process.Above-mentioned flexibel polyurethane grinding pad, after being pasted on grinding plate, carries out finishing process, according to circumstances with rule
Fix time and carried out cleaning based on pure water.
It addition, double-side polishing apparatus is configured to supply, discharges lapping liquid, become regulation with the supply flow rate of lapping liquid
The mode of value adjust the quantity delivered of lapping liquid and ground.
About the scavenging period of grinding pad carried out 3 times when grinding, the primary particle footpath of cabosil, lapping liquid
The compendency of the cabosil contained in pH, lapping liquid, the flow of lapping liquid, on the books in example 1 ~ 10 described later.
Use particle size distribution device (big electronics corporation system: FPAR-1000), before measuring grinding glass substrate
The particle size distribution of lapping liquid and the particle size distribution of the lapping liquid ground after glass substrate, ask according to respective particle size distribution
Go out d50 value, calculate the variable quantity (poor) of d50 value before and after the grinding of glass substrate, thus to the colloidal state oxygen contained in lapping liquid
The compendency of SiClx is evaluated.
It should be noted that above-mentioned d50 value refers to that aggregate-value when having been carried out number conversion by scatter intensity distribution becomes
The particle footpath of 50%.
Specifically, by utilizing the variable quantity of the d50 value before and after the grinding that below formula calculates to be evaluated.By
[the d50 value (nm) of the lapping liquid after grinding]-[the d50 value (nm) of the lapping liquid before grinding] represents.
When being below 15nm by the variable quantity of the d50 value before and after the grinding that above-mentioned formula calculates, the mill contained in lapping liquid
The coagulation of grain (cabosil) is nearly free from and favorable dispersibility (A), for slightly producing coagulation (B) during 16nm ~ 30nm.This
Outward, when more than 31nm, creating can be to the coagulation (C) of the degree that the grinding of the principal plane of glass substrate impacts.
In order to be met the glass base plate for magnetic recording carrier of the regulation of the present invention, it is preferably used and lapping liquid contains
The coagulation of abrasive particle is nearly free from and the lapping liquid of (A) of favorable dispersibility.This is because, hold agglutinophilic employing abrasive particle
During lapping liquid, the part that surface roughness Ra local is high may be produced on the surface of glass base plate for magnetic recording carrier, carry out
The glass substrate of smooth grinding (grinding for 3 times) carries out cleaning successively, the ultrasound wave being immersed under the state in detergent solution is clear
The ultrasonic waves for cleaning (precision cleaning) wash, being immersed under the state in pure water, utilizes methanol vapor to be dried.
For whole of the principal plane of glass base plate for magnetic recording carrier obtained by above order, by above-mentioned
Method have rated surface roughness Ra.
It addition, on the surface of the glass base plate for magnetic recording carrier obtained by above order, by following order
Film forming provides the multilayer film of the layer that is magnetic and as magnetic recording media, have rated EP incidence rate.
The surface of the glass base plate for magnetic recording carrier cleaned before having carried out film forming, uses at line style sputter equipment, depends on
The secondary stacking layer of NiFe as soft magnetic substrate coat, the Ru layer as nonmagnetic intermediate layer, as perpendicular magnetic recording layer
CoCrPtSiO2Grain structure layer.Then, CVD is utilized to form diamond-like carbon film as protective layer.Then, by dipping
Method defines the lubricating film containing PFPE.
For the magnetic recording media obtained, utilize said method to have rated EP mistake, obtained EP incidence rate.
The condition of the lapping liquid of the smooth grinding (grinding for 3 times) of principal plane is on the books in following example 1 ~ example 10.Example 1 ~ example 7
Being embodiment, example 8 ~ example 10 is comparative example.
On whole of the principal plane of the glass base plate for magnetic recording carrier processed under the processing conditions of example 1 ~ example 10,
Surface roughness Ra maximum/surface roughness Ra meansigma methods, surface roughness Ra meansigma methods (nm), surface roughness Ra standard
Deviation (nm) is as shown in table 1.And, the EP incidence rate (%) about magnetic recording media is the most as shown in table 1.
(example 1)
For by above-mentioned order, implementing the magnetic recording medium after the process till 2 grindings that principal plane grinds
Matter glass substrate, has carried out the smooth grinding (3 grinding steps) that principal plane grinds.
Smooth grinding use advances with pure water and has carried out the flexibel polyurethane grinding pad of cleaning in 10 minutes and containing 1 grain
Sub-footpath is that the cabosil of 12nm is implemented as the lapping liquid of the pH4 of abrasive particle.The abrasive particle contained in have rated lapping liquid
During the compendency of (cabosil), the variable quantity of the d50 value of the lapping liquid before and after grinding is below 15nm, for good (A).
It addition, the flow of the lapping liquid to supply to the abradant surface of double-side polishing apparatus is used for each magnetic recording media
Glass substrate becomes the mode of 6 ml/min and is ground.
Glass substrate after processing principal plane is implemented precision cleaning and is obtained glass base plate for magnetic recording carrier, measures magnetic
The surface roughness Ra of the principal plane of record medium glass substrate, is evaluated.
It addition, as it has been described above, the surface filming of glass base plate for magnetic recording carrier provide the layer that is magnetic multilayer film and
Form magnetic recording media, have rated EP incidence rate.
(example 2)
In the smooth grinding (3 grinding steps) that principal plane grinds, except making to supply to the abradant surface of double-side polishing apparatus
The flow of lapping liquid be beyond 2 ml/min for each glass base plate for magnetic recording carrier, by the side as example 1
Method has manufactured glass base plate for magnetic recording carrier and magnetic recording media (disk).
It should be noted that about the coagulation of the abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Property, it is similarly well (A) with the situation of example 1.
It addition, for the glass base plate for magnetic recording carrier obtained, magnetic recording media, evaluated in the same manner as example 1.
Result is as shown in table 1.
(example 3)
Principal plane grind smooth grinding (3 grinding steps) in, except set lapping liquid as pH5, set to twin grinding fill
The flow of the lapping liquid of the abradant surface supply put is beyond 2 ml/min for each glass base plate for magnetic recording carrier, passes through
Method as example 1 has manufactured glass base plate for magnetic recording carrier and magnetic recording media (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, is similarly well (A) with the situation of example 1.
It addition, for the glass base plate for magnetic recording carrier obtained, magnetic recording media, evaluated in the same manner as example 1.
Result is as shown in table 1.
(example 4)
In the smooth grinding (3 grinding steps) that principal plane grinds, except using colloidal silica contained in lapping liquid
The lapping liquid that primary particle footpath is 20nm of silicon, and set to double-side polishing apparatus abradant surface supply lapping liquid flow for
Each glass base plate for magnetic recording carrier is beyond 2 ml/min, has manufactured magnetic recording media by the method as example 1
With glass substrate and magnetic recording media (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, is similarly well (A) with the situation of example 1.
It addition, for the glass base plate for magnetic recording carrier obtained, magnetic recording media, evaluated in the same manner as example 1.
Result is as shown in table 1.
(example 5)
In the smooth grinding (3 grinding steps) that principal plane grinds, except using colloidal silica contained in lapping liquid
The lapping liquid that primary particle footpath is 25nm of silicon, and set to double-side polishing apparatus abradant surface supply lapping liquid flow for
Each glass base plate for magnetic recording carrier is beyond 2 ml/min, has manufactured magnetic recording media by the method as example 1
With glass substrate and magnetic recording media (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, is similarly well (A) with the situation of example 1.
It addition, for obtained glass base plate for magnetic recording carrier, magnetic recording media, commented in the same manner as example 1
Valency.Result is as shown in table 1.
(example 6)
In the smooth grinding (3 grinding steps) that principal plane grinds, except setting cabosil contained in lapping liquid
Primary particle footpath be 30nm, and set the flow of lapping liquid supplied to the abradant surface of double-side polishing apparatus each magnetic remembered
Recording medium glass substrate is beyond 2 ml/min, has manufactured glass base plate for magnetic recording carrier by the method as example 1
And magnetic recording media (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, is similarly well (A) with the situation of example 1.
It addition, for obtained glass base plate for magnetic recording carrier, magnetic recording media, commented in the same manner as example 1
Valency.Result is as shown in table 1.
(example 7)
In the smooth grinding (3 grinding steps) that principal plane grinds, except making lapping liquid be pH3, and set to twin grinding
The flow of the lapping liquid of the abradant surface supply of device is beyond 2 ml/min for each glass base plate for magnetic recording carrier, logical
The method as example 1 of crossing has manufactured glass base plate for magnetic recording carrier and magnetic recording media (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, is similarly well (A) with the situation of example 1.
It addition, for the glass base plate for magnetic recording carrier obtained, magnetic recording media, evaluated in the same manner as example 1.
Result is as shown in table 1.
(example 8)
In the smooth grinding (3 grinding steps) that principal plane grinds, do not carry out grinding of cleaning based on pure water except using
Mill pad, and set the flow of lapping liquid supplied to the abradant surface of double-side polishing apparatus for each magnetic recording media glass base
Plate is beyond 2 ml/min, has manufactured glass base plate for magnetic recording carrier and magnetic recording media (magnetic by the method as example 1
Dish).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, before and after grinding, particle size distribution d50 of lapping liquid carries out more than 31nm change, for (C).
It addition, for obtained glass base plate for magnetic recording carrier, magnetic recording media, commented in the same manner as example 1
Valency.Result is as shown in table 1.
(example 9)
In the smooth grinding (3 grinding steps) that principal plane grinds, except setting the scavenging period based on pure water of grinding pad
It is 5 minutes, and sets the flow of lapping liquid supplied to the abradant surface of double-side polishing apparatus for each magnetic recording media glass
Glass substrate is beyond 2 ml/min, has manufactured glass base plate for magnetic recording carrier and magnetic recording medium by the method as example 1
Matter (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, before and after grinding, the variable quantity of the d50 value of lapping liquid is more than 16nm and below 30nm, for (B).
It addition, for the glass base plate for magnetic recording carrier obtained, magnetic recording media, evaluated in the same manner as example 1.
Result is as shown in table 1.
(example 10)
In the smooth grinding (3 grinding steps) that principal plane grinds, except setting lapping liquid as pH2, and set the stream of lapping liquid
Amount is beyond 2 ml/min for each glass base plate for magnetic recording carrier, has manufactured magnetic note by the method as example 1
Recording medium glass substrate and magnetic recording media (disk).
It should be noted that coagulating about abrasive particle (cabosil) contained in the lapping liquid used when smooth grinding
Collection property, before and after grinding, the variable quantity of the d50 value of lapping liquid is below 15nm, for good (A).
It addition, for the glass base plate for magnetic recording carrier obtained, magnetic recording media, evaluated in the same manner as example 1.
Result is as shown in table 1.
From the result of table 1 it will be acknowledged that use the magnetic recording media glass of the example 1 ~ 7 of the regulation meeting the present invention
The EP incidence rate of the magnetic recording media that substrate is made all is reduced to less than 1.6%.In contrast, understand, as comparative example example 8 ~
The EP incidence rate of 10 is minimum is also up to about 2.5%.
This is considered because whole of the principal plane of the glass base plate for magnetic recording carrier of the present invention does not has rough surface
The highest region, degree Ra local, whole of principal plane smoothened, therefore form magnetosphere etc. and during as magnetic recording media,
Crystal grain can be suppressed to become big situation locally.
It is therefore contemplated that be because, it is possible to the generation of suppression magnetic noise, it is possible to increase based on magnetic head to magnetic recording media
The precision of read-write, it is possible to prevent the decline of packing density.
[table 1]
Claims (6)
1. a glass base plate for magnetic recording carrier, has a pair principal plane, it is characterised in that
On at least one principal plane, whole of the principal plane in the record regenerating region when comprising as magnetic recording media sets
Fixed area is 25 μm2～2500 μm2The meansigma methods of surface roughness Ra that is measured to of cancellate each evaluation region be
Below 0.07nm,
The maximum of described surface roughness Ra is less than 1.4 times of the meansigma methods of described surface roughness Ra.
Glass base plate for magnetic recording carrier the most according to claim 1, wherein,
The grid set on whole of the described principal plane in the record regenerating region when comprising as described magnetic recording media
1.3 times of the meansigma methods that maximum is described surface roughness Ra of the surface roughness Ra that each evaluation region of shape is measured to
Below.
Glass base plate for magnetic recording carrier the most according to claim 1 and 2, wherein,
The grid set on whole of the described principal plane in the record regenerating region when comprising as described magnetic recording media
The standard deviation of the surface roughness Ra that each evaluation region of shape is measured to is below 0.012nm.
Glass base plate for magnetic recording carrier the most according to claim 1 and 2, wherein,
The grid set on whole of the described principal plane in the record regenerating region when comprising as described magnetic recording media
The meansigma methods of the surface roughness Ra that each evaluation region of shape is measured to is below 0.06nm.
Glass base plate for magnetic recording carrier the most according to claim 3, wherein,
The grid set on whole of the described principal plane in the record regenerating region when comprising as described magnetic recording media
The meansigma methods of the surface roughness Ra that each evaluation region of shape is measured to is below 0.06nm.
6. a magnetic recording media, it uses the glass base plate for magnetic recording carrier according to any one of Claims 1 to 5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011-228322 | 2011-10-17 | ||
| JP2011228322A JP5212530B2 (en) | 2011-10-17 | 2011-10-17 | GLASS SUBSTRATE FOR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING MEDIUM USING THE GLASS SUBSTRATE FOR MAGNETIC RECORDING MEDIUM |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103050133A CN103050133A (en) | 2013-04-17 |
| CN103050133B true CN103050133B (en) | 2016-08-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210385806.8A Expired - Fee Related CN103050133B (en) | 2011-10-17 | 2012-10-12 | Glass base plate for magnetic recording carrier and employ the magnetic recording media of this glass base plate for magnetic recording carrier |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP5212530B2 (en) |
| CN (1) | CN103050133B (en) |
| MY (1) | MY152421A (en) |
| SG (1) | SG189628A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018101451A (en) * | 2015-04-23 | 2018-06-28 | 旭硝子株式会社 | Substrate for magnetic recording medium, magnetic recording medium, and manufacturing method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102171756A (en) * | 2008-09-30 | 2011-08-31 | Hoya株式会社 | Magnetic disc glass substrate and magnetic disc |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008293552A (en) * | 2007-05-22 | 2008-12-04 | Fujitsu Ltd | Substrate, magnetic recording medium, its manufacturing method, and magnetic storage device |
| JP2009289370A (en) * | 2008-05-30 | 2009-12-10 | Furukawa Electric Co Ltd:The | Glass substrate for magnetic disk |
-
2011
- 2011-10-17 JP JP2011228322A patent/JP5212530B2/en not_active Expired - Fee Related
-
2012
- 2012-10-03 SG SG2012073581A patent/SG189628A1/en unknown
- 2012-10-08 MY MYPI2012004477 patent/MY152421A/en unknown
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102171756A (en) * | 2008-09-30 | 2011-08-31 | Hoya株式会社 | Magnetic disc glass substrate and magnetic disc |
Also Published As
| Publication number | Publication date |
|---|---|
| SG189628A1 (en) | 2013-05-31 |
| JP5212530B2 (en) | 2013-06-19 |
| CN103050133A (en) | 2013-04-17 |
| MY152421A (en) | 2014-09-30 |
| JP2013089268A (en) | 2013-05-13 |
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